I have several high-end CAD and CAM programs (like AutoCAD and OrCAD -types) that will only work on XP. Some of the Modeling software at the most basic level START at about 35,000 $US, with others even higher. Each module of functionality added to the base program went for roughly 300 dollars per unit and up depending upon its area of useage. In 1990 dollars, not 2015. Probably cost more now, if a version was even available for the “newest” ‘doze OS.
Which is why I’m keeping an XP machine...